Flexible Gastro-intestinal Endoscopy - Clinical Challenges and Technical Achievements

Abstract

Flexible gastro-intestinal (GI) endoscopy is an integral diagnostic and therapeutic tool in clinical gastroenterology. High quality standards for safety, patients' comfort, and efficiency have already been achieved. Clinical challenges and technical approaches are discussed in this short review. Image enhanced endoscopy for further characterization of mucosal and vascular patterns includes dye-spray or virtual chromoendoscopy. For confocal laser endoscopy, endocytoscopy, and autofluorescence clinical value has not yet been finally evaluated. An extended viewing field provided by additional cameras in new endoscopes can augment detection of polyps behind folds. Attachable caps, flaps, or balloons can be used to flatten colonic folds for better visualization and stable position. Variable stiffness endoscopes, radiation-free visualization of endoscope position, and different overtube devices help reducing painful loop formation in clinical routine. Computer assisted and super flexible self-propelled colonoscopes for painless sedation-free endoscopy need further research. Single-use devices might minimize the risk of infection transmission in the future. Various exchangeable accessories are available for resection, dissection, tunneling, hemostasis, treatment of stenosis and closure of defects, including dedicated suturing devices. Multiple arm flexible devices controlled via robotic platforms for complex intraluminal and transmural endoscopic procedures require further improvement.

Fig. 1

Image enhanced endoscopy (IEE): a — High definition endoscopy (HDE; small ulcer in the ileum), b — chromoendoscopy (Dysplasia associated lesion/mass DALM in ulcerative colitis), c — Narrow band imaging (NBI; sessile serrated adenoma in the colon), d — Linked Color imaging (LCI; fundic gland cyst of the stomach), e — Blue light imaging (BLI; hyperplastic gastric polyp), f — Confocal laser endoscopy (CLE; Barrett's esophagus).

Fig. 2

Technical approaches to increase detection of polyps behind folds. a — Distal end of Full spectrum endoscopy (FUSE, EndoChoice) endoscope, b — Third eye Panoramic (Aventis) attached to a standard colonoscope, c — FUSE monitor with 3 images. The polyp is only seen on the left monitor. Mechanical devices attached to the endoscope tip: d — EndoRings, e — Endocuff.

Fig. 3

Superflexible, self-propelling colonoscopes: Invendosope C20: a — Motor roller driving unit, b — super flexible insertion tube (Invendo medical, Weinheim). ‘Inch worm’ endoscope (Endotics): c — Schematics of endoscope crawling around the splenic colon flexure, d — Endoscope tip with biopsy forceps (ERA Endoscopy, Peccioli).

Fig. 4

Single use endoscope. Invendo SC200: a — Hand held unit for electronically controlled tip angulation, b — single use insertion tube (Invendo medical, Weinheim).

Fig. 5

Endoscopic diagnosis and treatment in the same session, sessile serrated adenoma: a — The flat lesion is hardly visible with standard WLE. b — Demarcation after injection with methylene blue. c — Result after mucosectomy. d — Histology (courtesy of Prof. Sören Schröder) showing proliferation of crypts at the base of the specimen.

Fig. 6

Endoscopic therapy. Through the scope (TTS): a — Duodenal bleeding, Hemospray catheter. b — successful hemostasis after application of hemospray powder. Over the scope clip (OTSC): c — endoscopic view of a postoperative fistula in the colon, OTSC device on the tip of a standard colonoscope. d — Computed tomography scan with OTSC in situ after successful closure of the fistula.

Fig. 7

Multi-dimensional flexible endoscope. a — Anusbisope, b — close-up view of the endoscope tip with two flexible instrumentation arms (Storz, Tuttlingen).